WorldViz User Forum - exiting a yield statement

Hello there,

I have a question regarding exiting a yield statement, after a certain time elapsed. I am changing a global variable according to a keypress (using yield viztask.waitKeyDown) within a function, if that keypress should not happen, I want to exit the yield statement after a certain time interval. And continue the protocol with the unchanged global variable.
I might be wrong using yield, and there is some other way (I read about python threading?Running a timer parallel to yield?), could you point me to some example code? I couldn't find this scenario in the tutorial.
Thank you.

Code:

Step=1

Motion = 15

def control():

        global Motion

        ..... #dosomething with Motion

        for i in range(1,x)

                d = viz.Data()

                yield viztask.waitKeyDown(['y','n'],d) #or, if no key was pressed, after 2 sec exit yield

                if d.key == 'y':

                        Motion = Motion - Step

                elif d.key == 'n':

                        Motion = Motion + Step